1. Field of the Invention
The invention relates to a device for connecting movable parts with structural components of airplanes or the like, including at least one fitting provided with at least one bearing.
The device according to the invention is applicable for airplanes, helicopters and other aircraft as well as for other vehicles such as, e.g., high-speed ships or high-speed cars. The term “movable parts” serves to denote, in particular, spoilers, landing flaps, control surfaces or the like, which are required to control an airplane or the like and to assist in the take-off, landing and moving procedures. Spoilers are interference flaps provided on the rear upper sides of the wings of airplanes, which, on the one hand, serve as braking flaps during landing and, on the other hand, also assist the aileron if used asymmetrically.
The spoiler produces a resistance which destroys part of the ascending force. The term “structural components”, above all, encompasses the airfoils of airplanes or the like. The invention is, however, also applicable to helicopters, in which the wing is formed by a rotor blade including movable control flaps.
2. Prior Art
Movable parts such as spoilers, landing flaps, control surfaces or the like are usually connected with fittings made of metals such as, for instance, aluminum or titanium alloys. The connection of the fittings with the movable part in most cases is realized by the aid of rivets or detachable screw connections. The fitting includes at least one bearing via which the movable connection with the structural component such as, for instance, the wing, is effected. Since extremely high loads act on the movable parts and hence the fittings of, in particular, an airplane, these must be especially stable. The fittings, which are mostly made of the materials mentioned by forging or milling, are very expensive in terms of production. In order to lower fuel expenses, it is constantly aimed to further reduce the weight of airplanes or the like. By producing various components and also spoilers, landing flaps, control surfaces or the like of synthetic materials and, in particular, composite materials, a considerable reduction of the weight of such airplanes or the like has already been reached. The interface between a part made of a synthetic material and a fitting made of a metal is subject to undesired dynamic effects due to different thermal expansions of the components. With the materials usually used in aircraft technology, this problem is particularly evident, since composite material have negative temperature coefficients, while aluminum or titanium alloys have positive temperature coefficients. On account of the particularly high temperature deviations of between about −70° and +80° faced primarily in aviation, accordingly high shearing forces act on the connecting elements between such synthetic components and metal fittings. As a result, a higher number of connecting elements like screws or rivets must be provided. Usually, even one third of all connecting elements is employed merely because of the shearing forces caused by different thermal expansions. In addition to an increased complexity and elevated costs, the higher number of connecting elements also involves higher weights.
U.S. Pat. No. 4,213,587 A discloses an articulated connection between flaps and structural components, which is comprised of a fitting anchored in the structural component and screwed therewith and a bearing pin anchored in the movable part. Due to the different thermal expansion coefficients mentioned above, undesired stresses occur between the fitting and the structural component as well as the fitting and the movable part. Moreover, the anchorage and assemblage of the fitting parts with the structural component and the movable part are very cumbersome with the respective parts exhibiting high weights.
Also U.S. Pat. No. 5,098,043 A discloses a movable connection between an wing and a control surface, in which a fitting is connected with the flap via structural components provided in the control surface and is rotatably mounted on the wing via a pin. The aforementioned problems faced by different thermal expansions and the weight involved apply also in that case.
A connecting means used to connect a movable flap with a rotor blade of a helicopter is described in DE 199 09 257 A1, wherein the flap is connected with the rotor blade or wing via a torsionally elastic and deflection-resistant rod element. The connection between the rod element and the wing or the flap, respectively, is realized by means of an adhesive and/or by screws. The torsionally elastic and deflection-resistant rod element advantageously is made in one piece of a glued fiber composite material. Such a torsionally elastic and deflection-resistant rod element, however, allows for only slight movements of the flap relative to the rotor blade, which would be too small for the application of spoilers or landing flaps or the like in aircraft.
U.S. Pat. No. 4,243,189 A shows a temperature-compensated connection between a wing and an elevator, which is comprised of different materials having different thermal expansion coefficients. The different expansion values are compensated by the arrangement of articulately connected supports. The construction is, however, very complex and also unable to avoid the problems involved in the connections of the supports with the airfoil or the elevator.
EP 532 016 A1 describes a spoiler for the wing of an airplane, which comprises fittings that are connected with the spoiler in a manner so as to minimize the shearing forces. That connection is achieved by a special geometric configuration of the attachment surfaces of the fittings as well as the lower side of the spoiler, to which the fittings are fastened.